The aims of this study are to develop a novel instrument for the accurate on-site determination of total carbon dioxide in the atmosphere and seawater and to measure accurately and rapidly the exchange rate and mass of carbon dioxide between the atmosphere and the sea on site. In the present study, we developed a new portable analyzer and a new detection method for the carbon dioxide in the atmosphere and the total carbonate in the seawater, and also developed a method for the preparation of carbonate-free purified water and for the determination and the removal of carbonate in alkaline solutions. By using such novel methods, accurate and sensitive determination of carbon dioxide and carbonate was achieved, the carbonate species dissolved in seawater was clarified on the basis of the equilibrium principle, and the accurate distribution behavior of carbon dioxide between the atmosphere and the sea was clarified. The main results obtained in this study are as follows.1. Development of a
… Moreportable analyzer for total carbonate in waters : This system was used for the determination of total carbonate in water samples and carbon dioxide in the atmosphere on site. The system is based on a flow injection technique coupled with a gas-diffusion apparatus, which was developed in the present study and is very effective for the diffusion of carbon dioxide. This system can work by a 12 V battery, as well as 100 V, and is 8 kg weigh, 16 cm wide x 16 cm high x 32 cm deep. The aqueous samples, such as sea, river and rain waters, can be injected directly and measured within 3 min.2. Development of highly sensitive detection reagent for carbonate : About twenty-five azo dyes were synthesized in this study, and a novel reagent was found. The reagent can be used for sensitive detection of total carbonate in water samples at 450 nm of LED.3. Development of the determination method for carbon dioxide in the atmosphere : The method developed in this study is based on the adsorption of carbon dioxide in air samples into a triethanolamine solution in plastic syringes and the measurement of carbonate in the adsorption solutions by the newly developed analyzer.4. Analysis of the dissolved states of carbon dioxide in sea water : The estimation of the dissolved species and their concentrations in sea water samples could be achieved by solving the equilibriums existing in the solutions, and the analysis of the distribution equilibrium and the distribution rate of carbon dioxide between the air and the water phase were carried out, for the first time, in this study. Less